This invention relates generally to pet doors, and more particularly to magnetically actuated pet door locks to prevent ingress of unauthorized pets.
Pet doors are generally known in the prior art for allowing ingress and egress of pets, such as cats or dogs, from dwellings without the necessity of the owner letting the pet in or out. These doors provide the pet with freedom to come and go at will.
One type of pet door takes the form of a series of triangular plastic or rubber members arranged to form an iris. The pet can easily enter and exit the dwelling through the iris, but stray animals may also enter the dwelling. Another type of pet door utilizes flexible flaps over an opening for allowing the owner's pet to enter or exit. Single flaps have been used as shown in U.S. Pat. No. 3,184,802. Dual flexible flaps, mounted one within the other, have also been used. A smaller, inner flap is attached to a larger, outer flap which swings to one side only. The smaller flap rests against the lip of an opening through the larger flap so that it can swing to the other side only. The flaps also contain magnets and iron slugs or discs for holding the two flaps together while the outer flap swings to one side. The pet can thus pass through the opening in the outer flap in one direction and through a larger opening in the door in the other direction. The outer flap also has magnets molded along the bottom to keep it closed against iron slugs or discs until the pet pushes against it. The problem with these pet doors is that they allow stray animals to pass through the door.
In order to bar stray animals from passing through the pet door while allowing only one's own pet to pass, some latching scheme must be provided. One scheme disclosed in U.S. Pat. No. 4,022,263 employs a magnetic reed switch actuated by a permanent magnet attached to the pet's collar. The problem is that the magnet must come very close to the reed switch to close it. To assure that, a first iris-type door is provided, and the reed switch is mounted near the center of the iris. The actuated reed switch energizes a solenoid to unlock a hinged door beyond, thus allowing the owner's pet to enter in one direction. The lock is provided as a one-way latch to permit the pet to pass freely in the other direction. Such a system is relatively complex and costly to install because it requires a chamber having an iris-type door and a hinged door. Moreover, unless the magnet is in the proper position on the pet's neck to contact, or very nearly contact, the reed switch, it will not be actuated. Accordingly, it is an object of the present invention to provide an improved pet door and latch.